title: Observation of Cu-N3- stretching and N3- asymmetric stretching bands for mono-azide adduct of Rhus vernicifera laccase.
abstract: Mono-azide adduct of Rhus vernicifera laccase, a multicopper oxidase containing one type-1 (blue) copper, one type-2 (non-blue normal) copper, and a pair of type-3 (binuclear and EPR silent) coppers, of which type-2 and type-3 coppers constitute a trinuclear site, was investigated with resonance Raman (RR) and Fourier transform infrared (FT-IR) spectroscopies as a step toward elucidation of the structure and function of the trinuclear site. The Cu-N3- stretching (vCu-N3-) RR band was observed for azide-bound multicopper oxidases for the first time. The vCu-N3- band was located at 400 cm-1 for mono-14N3- laccase, which shifted to 396 cm-1 with the 15N14N14N3- analog. The N3- asymmetric stretching (v(N3-)asym) band was observed by FT-IR spectroscopy at 2035 cm-1 for mono-14N3- laccase and at 2025 cm-1 for the 15N14N14N3- analog. The vCu-N3- and v(N3-)asym frequencies and their 15N14N14N- isotope shifts for azido laccase correspond well with those of metazido hemocyanin, indicating that both derivatives should have a similar binding geometry of azide.
authors.affiliation: Department of Chemistry, Graduate School of Science, Nagoya University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hirota
authors.forename: H
authors.initials: H
authors.lastname: Matsumoto
authors.forename: H W
authors.initials: HW
authors.lastname: Huang
authors.forename: T
authors.initials: T
authors.lastname: Sakurai
authors.forename: T
authors.initials: T
authors.lastname: Kitagawa
authors.forename: O
authors.initials: O
authors.lastname: Yamauchi
mesh_terms: D001386:Azides / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006433:Hemocyanins / Q000737:chemistry; D042845:Laccase; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010947:Plants, Toxic; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D012251:Toxicodendron / Q000201:enzymology*
chemical_list: D001386:Azides; D003300:Copper; D006433:Hemocyanins; D010088:Oxidoreductases; D042845:Laccase